This invention relates generally to prefabricated drainage units and more particularly to improved drainage matrices therefor in the form of corrugated thermoplastic netting. The corrugated netting is thermoformed to provide a plurality of upstanding projections, sometimes referred to as corrugations herein, providing flow channels through which ground water may drain.
As an alternative to aggregate drains, prefabricated groundwater drainage arrangements of the general type contemplated herein and referred to as prefabricated drainage units have been suggested in the art and are described in several U.S. Patents. These patents include U.S. Pat. No. 3,563,038 and U.S. Pat. No. 3,654,765; along with the various patents cited or otherwise referred to in those patents. Such units find use in road edge drains, wick or fin drains and foundation drains, among others.